The plugin is another try on Vim marks. Often I end up using two separate mark groups for navigation (a-f and t-z) so I created a plugin to simplify this. Version 1.1 adds the ability to display marks in quickfix and location list windows.

Provided mappings:
<Plug>ToggleMarkAZ - mark/unmark current position, if there are multiple marks on the line, remove the first
<Plug>ToggleMarkZA - mark/unmark current position, if there are multiple marks on the line, remove the last
<Plug>ForceMarkAZ - add an unused mark starting from a, even if the position is marked
<Plug>ForceMarkZA - add an unused mark starting from z, even if the position is marked
<Plug>NextMarkPos - go to next mark
<Plug>PrevMarkPos - go to prev mark
<Plug>NextMarkLexi - go to previous mark in lexicographical order
<Plug>PrevMarkLexi - go to next mark in lexicographical order
<Plug>MarksLoc - open location list window with local mark positions
<Plug>MarksQF - open quickfix window with marks

So
\a and \z will toggle a mark at current line
\A and \Z force another mark
\m and \M go to next/prev mark
\l and \L go to next/prev mark alphabetically
\w and \W populate location list/quickfix window with marks

Also I suggest to install a plugin to visualise marks e.g. quickfixsigns (vimscript#2584)